1. Field of the Invention
This invention relates to the pipe end surface bevelling art and more particularly to a cam following pipe bevelling tool arrangement adapted to follow the contours of the external surface of a pipe to be bevelled.
2. Background of the Invention
In many applications it is necessary to prepare properly the end surface of a pipe. For example, pipe sections are often joined together by welding and, as such, the end surface of each pipe section must be properly prepared. One step in the preparation is the cutting of a land or flat on the end surface of the pipe lying in a plane perpendicular to the center line of the pipe. The flat provided on the end surface extends from the inside diameter of the pipe radially outwardly a predetermined distance and a bevel extending from the end of the flat to the external surface of the pipe may also be required. When two such properly prepared end surfaces of pipes are placed adjacent they may be welded in the resulting V-shaped groove formed by the two bevelled surfaces.
In many applications, however, it has been found that the pipe sections, while generally of a constant wall thickness may be out-of-round. That is, often times in the field, such pipe sections are stored in a vertically stacked arrangement. The weight of such pipe section bearing upon those in the lower layers often causes a deformation of the pipe to an out-of-round condition. Consequently, such pipe sections have a nominal center line and the internal and external surfaces of the pipe vary in the radial dimension from this nominal center line. However, it is still desired to provide even in such out-of-round pipe sections the constant land and bevel in the end surfaces thereof.
Prior art devices for preparation of the end surfaces of pipe sections have generally comprised various types of tools which may be coupled to or placed adjacent to the end surface of the pipe and rotated about the center line, or nominal center line of the pipe at a fixed radial distance thereof with the tool position and/or shape providing the desired configuration of the cut made in the end surface of the pipe. Rotating at a fixed radial distance, therefore, a constant configuration of the end surface could not be obtained on out-of-round pipe due to the radial distance variation of the pipe walls from the nominal center line thereof.
Consequently, there has long been a need for a pipe end surface bevelling tool arrangement which can provide a constant bevel on the end surface of a pipe despite the out-of-round condition of the pipe.